Electronic cigarette with mass air flow sensor

ABSTRACT

In accordance with one aspect of the present invention there is provided an electronic smoking device comprising a flow channel and an atomizer. The flow channel can comprise an incoming airflow opening, an incoming airflow pathway, a sensor assembly, and an outgoing airflow opening. The atomizer can be fluidly coupled to the flow channel. The flow channel can be configured to direct an airflow from the incoming airflow opening, through the incoming airflow pathway, over the sensor assembly, and through the outgoing airflow opening. The electronic smoking device can further be configured to pass the airflow over the atomizer.

This application is a continuation of U.S. patent application Ser. No.15/930,061, filed May 12, 2020, which is a continuation of U.S. patentapplication Ser. No. 15/219,214, filed Jul. 25, 2016, now U.S. Pat. No.10,757,973, both of which are incorporated herein by reference.

FIELD OF INVENTION

The present invention relates generally to electronic smoking devicesand in particular electronic cigarettes.

BACKGROUND OF THE INVENTION

An electronic smoking device, such as an electronic cigarette(e-cigarette), typically has a housing accommodating an electric powersource (e.g., a single use or rechargeable battery, electrical plug, orother power source), and an electrically operable atomizer. The atomizervaporizes or atomizes liquid supplied from a reservoir and providesvaporized or atomized liquid as an aerosol. Control electronics controlthe activation of the atomizer. In some electronic cigarettes, anairflow sensor is provided within the electronic smoking device, whichdetects a user puffing on the device (e.g., by sensing an under-pressureor an airflow pattern through the device). The airflow sensor indicatesor signals the puff to the control electronics to power up the deviceand generate vapor. In other e-cigarettes, a switch is used to power upthe e-cigarette to generate a puff of vapor.

In prior art eCigs, the pressure sensor is configured to sense a user'sdraw on the eCig and transmit an activation signal to the heating coilto vaporize the liquid solution. However, these pressure sensors can belarge and costly.

SUMMARY OF THE INVENTION

In accordance with one aspect of the present invention there is providedan electronic smoking device comprising a flow channel and an atomizer.The flow channel can comprise an incoming airflow opening, an incomingairflow pathway, a sensor assembly, and an outgoing airflow opening. Theatomizer can be fluidly coupled to the flow channel. The flow channelcan be configured to direct an airflow from the incoming airflowopening, through the incoming airflow pathway, over the sensor assembly,and through the outgoing airflow opening. The electronic smoking devicecan further be configured to pass the airflow, at least in part, overthe atomizer.

The characteristics, features and advantages of this invention and themanner in which they are obtained as described above, will become moreapparent and be more clearly understood in connection with the followingdescription of exemplary embodiments, which are explained with referenceto the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, the same element numbers indicate the same elements ineach of the views:

FIG. 1 is a schematic cross-sectional illustration of an exemplarye-cigarette.

FIG. 2A is a partial exploded assembly view of an eCig battery housing,consistent with various aspects of the present disclosure.

FIG. 2B is a partial exploded assembly view of an eCig battery housing,consistent with various aspects of the present disclosure.

FIG. 3 is an example of a microcontroller that is constructed accordingto an aspect of the disclosure.

FIG. 4 is an example of a flow sensor that is constructed according toan aspect of the disclosure.

FIGS. 5A and 5B are examples of signal amplification and filteringthrough a single amplifier or multiple amplifiers.

FIG. 6 is an electrical diagram of an eCig comprising a first and secondthermopile.

FIG. 7 is an electrical diagram of an eCig comprising one thermopile.

FIGS. 8A and 8B are an example of a flow channel according to theprinciples of the disclosure.

FIG. 9 is a side view of one embodiment of a sensor assembly.

FIG. 10 is a schematic view of another embodiment of a sensor assembly.

FIG. 11A is a schematic view of another embodiment of a sensor assembly.

FIG. 11B is a schematic view of an embodiment of a sensor.

FIGS. 12A-12C are schematics of several embodiments of flow channelsaccording to the disclosure.

FIG. 13 is a graph illustrating one embodiment of the power deliveredfor various flow rates.

FIG. 14 is a graph illustrating several embodiments of response signalsfor various flow rates.

FIG. 15 is a graph illustrating one embodiment of a flow rate over time.

FIG. 16 is a graph illustrating several embodiments of response signalsfor various flow rates.

FIG. 17 is a flowchart illustrating one embodiment of a process forinterpreting signals according to the disclosure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Throughout the following, an electronic smoking device will beexemplarily described with reference to an e-cigarette. As is shown inFIG. 1, an e-cigarette 10 typically has a housing comprising acylindrical hollow tube having an end cap 12. The cylindrical hollowtube may be a single-piece or a multiple-piece tube. In FIG. 1, thecylindrical hollow tube is shown as a two-piece structure having a powersupply portion 14 and an atomizer/liquid reservoir portion 16. Togetherthe power supply portion 14 and the atomizer/liquid reservoir portion 16form a cylindrical tube which can be approximately the same size andshape as a conventional cigarette, typically about 100 mm with a 7.5 mmdiameter, although lengths may range from 70 to 150 or 180 mm, anddiameters from 5 to 28 mm.

The power supply portion 14 and atomizer/liquid reservoir portion 16 aretypically made of metal (e.g., steel or aluminum, or of hardwearingplastic) and act together with the end cap 12 to provide a housing tocontain the components of the e-cigarette 10. The power supply portion14 and the atomizer/liquid reservoir portion 16 may be configured to fittogether by, for example, a friction push fit, a snap fit, a bayonetattachment, a magnetic fit, or screw threads. The end cap 12 is providedat the front end of the power supply portion 14. The end cap 12 may bemade from translucent plastic or other translucent material to allow alight-emitting diode (LED) 18 positioned near the end cap to emit lightthrough the end cap. Alternatively, the end cap may be made of metal orother materials that do not allow light to pass.

An air inlet may be provided in the end cap, at the edge of the inletnext to the cylindrical hollow tube, anywhere along the length of thecylindrical hollow tube, or at the connection of the power supplyportion 14 and the atomizer/liquid reservoir portion 16. FIG. 1 shows apair of air inlets 20 provided at the intersection between the powersupply portion 14 and the atomizer/liquid reservoir portion 16.

A power supply, preferably a battery 22, the LED 18, control electronics24 and, optionally, an airflow sensor 26 are provided within thecylindrical hollow tube power supply portion 14. The battery 22 iselectrically connected to the control electronics 24, which areelectrically connected to the LED 18 and the airflow sensor 26. In thisexample, the LED 18 is at the front end of the power supply portion 14,adjacent to the end cap 12; and the control electronics 24 and airflowsensor 26 are provided in the central cavity at the other end of thebattery 22 adjacent the atomizer/liquid reservoir portion 16.

The airflow sensor 26 acts as a puff detector, detecting a user puffingor sucking on the atomizer/liquid reservoir portion 16 of thee-cigarette 10. The airflow sensor 26 can be any suitable sensor fordetecting changes in airflow or air pressure, such as a microphoneswitch including a deformable membrane which is caused to move byvariations in air pressure. Alternatively, the sensor may be, forexample, a Hall element or an electro-mechanical sensor.

The control electronics 24 are also connected to an atomizer 28. In theexample shown, the atomizer 28 includes a heating coil 30 which iswrapped around a wick 32 extending across a central passage 34 of theatomizer/liquid reservoir portion 16. The central passage 34 may, forexample, be defined by one or more walls of the liquid reservoir and/orone or more walls of the atomizer/liquid reservoir portion 16 of thee-cigarette 10. The coil 30 may be positioned anywhere in the atomizer28 and may be transverse or parallel to a longitudinal axis of acylindrical liquid reservoir 36. The wick 32 and heating coil 30 do notcompletely block the central passage 34. Rather an air gap is providedon either side of the heating coil 30 enabling air to flow past theheating coil 30 and the wick 32. The atomizer may alternatively useother forms of heating elements, such as ceramic heaters, or fiber ormesh material heaters. Nonresistance heating elements such as sonic,piezo, and jet spray may also be used in the atomizer in place of theheating coil.

The central passage 34 is surrounded by the cylindrical liquid reservoir36 with the ends of the wick 32 abutting or extending into the liquidreservoir 36. The wick 32 may be a porous material such as a bundle offiberglass fibers or cotton or bamboo yarn, with liquid in the liquidreservoir 36 drawn by capillary action from the ends of the wick 32towards the central portion of the wick 32 encircled by the heating coil30.

The liquid reservoir 36 may alternatively include wadding (not shown inFIG. 1) soaked in liquid which encircles the central passage 34 with theends of the wick 32 abutting the wadding. In other embodiments, theliquid reservoir may comprise a toroidal cavity arranged to be filledwith liquid and with the ends of the wick 32 extending into the toroidalcavity.

An air inhalation port 38 is provided at the back end of theatomizer/liquid reservoir portion 16 remote from the end cap 12. Theinhalation port 38 may be formed from the cylindrical hollow tubeatomizer/liquid reservoir portion 16 or may be formed in an end cap.

In use, a user sucks on the e-cigarette 10. This causes air to be drawninto the e-cigarette 10 via one or more air inlets, such as air inlets20, and to be drawn through the central passage 34 towards the airinhalation port 38. The change in air pressure which arises is detectedby the airflow sensor 26, which generates an electrical signal that ispassed to the control electronics 24. In response to the signal, thecontrol electronics 24 activate the heating coil 30, which causes liquidpresent in the wick 32 to be vaporized creating an aerosol (which maycomprise gaseous and liquid components) within the central passage 34.As the user continues to suck on the e-cigarette 10, this aerosol isdrawn through the central passage 34 and inhaled by the user. At thesame time, the control electronics 24 also activate the LED 18 causingthe LED 18 to light up, which is visible via the translucent end cap 12.Activation of the LED may mimic the appearance of a glowing ember at theend of a conventional cigarette. As liquid present in the wick 32 isconverted into an aerosol, more liquid is drawn into the wick 32 fromthe liquid reservoir 36 by capillary action and thus is available to beconverted into an aerosol through subsequent activation of the heatingcoil 30.

Some e-cigarette are intended to be disposable and the electric power inthe battery 22 is intended to be sufficient to vaporize the liquidcontained within the liquid reservoir 36, after which the e-cigarette 10is thrown away. In other embodiments, the battery 22 is rechargeable andthe liquid reservoir 36 is refillable. In the cases where the liquidreservoir 36 is a toroidal cavity, this may be achieved by refilling theliquid reservoir 36 via a refill port (not shown in FIG. 1). In otherembodiments, the atomizer/liquid reservoir portion 16 of the e-cigarette10 is detachable from the power supply portion 14 and a newatomizer/liquid reservoir portion 16 can be fitted with a new liquidreservoir 36 thereby replenishing the supply of liquid. In some cases,replacing the liquid reservoir 36 may involve replacement of the heatingcoil 30 and the wick 32 along with the replacement of the liquidreservoir 36. A replaceable unit comprising the atomizer 28 and theliquid reservoir 36 may be referred to as a cartomizer.

The new liquid reservoir may be in the form of a cartridge (not shown inFIG. 1) defining a passage (or multiple passages) through which a userinhales aerosol. In other embodiments, the aerosol may flow around theexterior of the cartridge to the air inhalation port 38.

Of course, in addition to the above description of the structure andfunction of a typical e-cigarette 10, variations also exist. Forexample, the LED 18 may be omitted. The airflow sensor 26 may be placed,for example, adjacent to the end cap 12 rather than in the middle of thee-cigarette. The airflow sensor 26 may be replaced by, or supplementedwith, a switch which enables a user to activate the e-cigarette manuallyrather than in response to the detection of a change in airflow or airpressure.

Different types of atomizers may be used. Thus, for example, theatomizer may have a heating coil in a cavity in the interior of a porousbody soaked in liquid. In this design, aerosol is generated byevaporating the liquid within the porous body either by activation ofthe coil heating the porous body or alternatively by the heated airpassing over or through the porous body. Alternatively the atomizer mayuse a piezoelectric atomizer to create an aerosol either in combinationor in the absence of a heater.

FIG. 2A is a partial exploded assembly view of an eCig power supplyportion 212 (also referred to as a power supply portion), consistentwith various aspects of the present disclosure. The power supply portion212 houses a number of electrical components that facilitate there-charging and re-use of the power supply portion 212 with disposableand refillable atomizer/liquid reservoir portions (14 as shown in FIG.1), which are also referred to as atomizer/liquid reservoir portions. Abattery 218 is electrically coupled to controller circuitry 222 on aprinted circuit board. An airflow sensor 224 for determining one or morecharacteristics of a user's draw from the eCig is also located on theprinted circuit board, and communicatively coupled to the controllercircuitry 222. In various embodiments consistent with the presentdisclosure, the airflow sensor 224 may be a mass airflow sensor, apressure sensor, a velocity sensor, a heater coil temperature sensor, orany other sensor that may capture relevant draw characteristics (eitherdirectly or through indirect correlations). In the present embodiment,the airflow sensor 224 is a mass airflow sensor that determines the flowof air across the airflow sensor 224. The measured flow of air is thendrawn through the atomizer/liquid reservoir portion, where heater coilsatomize eCig juice into the air, and into a user's mouth. Accordingly,by measuring the mass flow rate of air through the power supply portion212, the controller circuitry 222 may adjust a heating profile of aheating coil in a atomizer/liquid reservoir portion (e.g., power, lengthof time, etc.), as well as provide a variable indication of the strengthof the draw—by way of LEDs 220 _(A-E), which may be independentlyaddressed by the controller circuitry or powered at varying intensitiesto indicate characteristics indicative of the eCig's functionality. Forexample, varying the illumination intensity based on the sensed massairflow. In further embodiments, the LEDs may also indicate otherfunctional aspects of the eCig, such as remaining battery life,charging, sleep mode, among others.

In various embodiments of the present disclosure, electrical pinsextending from the printed circuit board may be electrically coupled toa atomizer/liquid reservoir portion, and thereby allow for both energytransfer and data communication between the power supply portion 212 andthe atomizer/liquid reservoir portion (not shown). In various otherembodiments, pins may extend from a surface of the printed circuit boardto an exterior of the power supply portion to facilitate charging anddata communication with external circuitry.

To provide user indications of status, power remaining, use, errormessages, among other relevant information, a flexible printed circuitboard 221 is communicatively coupled to controller circuitry 222 viawire leads 242 _(A-B). The flexible circuit board 221 may include one ormore light sources. In the present embodiment, the flexible circuitboard 221 includes LEDs 220 _(A-E). When assembled into the rest of thepower supply portion 212, the LEDs 220 _(A-E) both illuminate acircumferential portion of light guide 216, and a tip diffuser 246 thatilluminates a distal end of the light guide 216. The tip diffuser 246and the light guide 216 together facilitate even illumination of thedistal end of the power supply portion 212 in response to the activationof the LEDs 220 _(A-E).

As shown in FIG. 2A, once electrically coupled to one another (e.g., bysolder), battery 218, flexible printed circuit board 221, and a printedcircuit board containing controller circuitry 222 and airflow sensor 224are encased by upper sub-assembly housing 240 and lower sub-assemblyhousing 241. In one embodiment, the upper sub-assembly housing 240 andthe lower sub-assembly housing 241 can create a flow channel. The flowchannel created by the upper sub-assembly housing 240 and the lowersub-assembly housing 241 can direct airflow over the airflow sensor. Thesub-assembly housing portions positively locate the various componentswith the sub-assembly. In many embodiments, the sub-assembly housingportions utilize locating pins and integral locking features to maintainthe sub-assembly after assembly.

Once assembly is complete on the sub-assembly, the sub-assembly may beslid into tube 245 from one end, and tip diffuser 246 andcircumferential light guide 216 may be inserted from the opposite end ofthe tube to complete assembly of power supply portion 212. By way of thedistal tip of the circumferential light guide 216 and etch pattern 248in tube 245, LEDs 220 _(A-E) may illuminate evenly around a distalcircumferential portion of the tube 245, and a distal tip of the powersupply portion 212.

In various embodiments of the present disclosure, one or more keyingfeatures may be present on an exterior surface of upper and/or lowersub-assembly housing portions 240 and 241. When the sub-assembly isinserted into tube 245, mating keying features along an inner surface ofthe tube 245 rotationally align the tube and the sub-assembly along alongitudinal axis and prevent the sub-assembly from spinning therein.

The use of a sub-assembly during manufacturing helps minimize assemblycomplexity, as well as reduce overall assembly time. Moreover, thesub-assembly helps to mitigate scrap as the sub-assembly allows forrapid re-work of a power supply portion 212, such as when electroniccircuitry within the power supply portion fails in testing. Moreover,the sub-assembly helps to mitigate common failure modes of eCigs duringits useful life by reducing shock and vibration related damage to thesub-components. Specifically, by positively locating controllercircuitry 222 and flexible circuit board 221 within the upper and lowersub-assembly housing portions 240 and 241, wire leads 242 _(A-B) andbonding pads electrically coupling the circuitry are less likely toexperience failure modes. For example, stress fractures at a solderjoint on a bonding pad.

In various embodiments of the present disclosure, pattern 248 on tube245 may include various different patterns, shapes, images and/or logos.In the present embodiment, the pattern 248 is a plurality of trianglespositioned in proximity to one another. The pattern 248 may be laseretched onto a painted surface of the tube 245, silk screened, drilled orotherwise cut into an outer surface of the tube 245, and/or the tubeitself can be translucent or semi-translucent and the pattern may bedisposed on an outer surface 350 of circumferential light guide 316. Thepattern 248 on an outer surface of tube 245 allows controller circuitry222 to provide visual indications of the eCigs functionality via lightbeing emitted from LEDs 220 _(A-E) through circumferential light guide216. The eCig may provide a plurality of visual indications by varyingthe brightness (e.g., LED duty cycle), color (e.g., output frequencyand/or multi-diode LEDs), location, on/off time, patterning, among othervisually distinguishable characteristics.

FIG. 2B is a partial exploded assembly view of an eCig power supplyportion sub-assembly 213, consistent with various aspects of the presentdisclosure. As shown in FIG. 2B, flex circuit 221 and battery 218 areelectrically coupled to controller circuitry 222 via wire leads whichare soldered on to the controller circuitry. Contacts 225 _(A-C) (alsoreferred to as electrical pins) are also electrically coupled to thecontroller circuitry 222 and extend toward apertures within the uppersub-assembly housing 240. The contacts 225 _(A-C) facilitate electricalcommunication between the controller circuitry 222 and an externalcircuit, as well as charging the battery 218.

When assembled, flex circuit 221 extends over and around battery 218.The battery being circumferentially enclosed by upper and lowersub-assembly housing portions 240 and 241. Controller circuitry 222 issandwiched between spacer 229 and MAF gasket 228; the spacer and MAFgasket contacting respective surfaces of upper and lower sub-assemblyhousing portions 240 and 241 and thereby positively locate thecontroller circuitry within the sub-assembly. The spacer 229 includes aninner aperture that functions as a light guide to deliver light from anLED on the controller circuitry 222 through an aperture within the lowersub-assembly housing 241. The MAF gasket 228 facilitates an airflowpassage between the controller circuitry 222 and the upper sub-assemblyhousing 240. The MAF gasket 228 both forms a seal between the controllercircuitry 222 and the upper sub-assembly housing to direct the airflowpast the airflow sensor 224 (as shown in FIG. 2A), as well as tomaintain a desired cross-sectional area of the airflow passage in thevicinity of a mass airflow sensor.

Female connector port 258 mates to a male connector port on aatomizer/liquid reservoir portion of the eCig, and provides a flow ofair via a fluid outlet, and power and data communication signals via aplurality of electrical contacts that are communicatively coupled tocorresponding electrical contacts on the male connector port (when themale and female connector ports are mated to one another). In variousembodiments of the present disclosure, the male and female connectorports are hemicylindrical in shape. As used herein, “hemicylindrical”describes parts having the shape of a half a cylinder, as well as partsthat include a larger or smaller portion of a cylinder when cut by aplane that is parallel to the longitudinal axis (or lengthwise) of thecylinder. An airflow gasket 227 is inserted into the female connectorport 258 and facilitates a fluid seal with the mating male connectorport. In one particular embodiment, airflow sensor 224 is a mass airflowsensor that measures a flow of air through the eCig, the airflow gasket227 prevents additional air from entering the airflow into theatomizer/liquid reservoir portion (or the escape of air from theairflow) after the mass airflow sensor has measured the airflow.

Once the sub-assembly 213 has been assembled and inserted into an outertube 245, a locking pin 226 is inserted through corresponding aperturesin the outer tube and the upper sub-assembly housing 240 to axially androtationally couple the sub-assembly 213 within the power supply portion212.

FIG. 3 shows an example of the microcontroller 320 constructed accordingto an aspect of the disclosure. The microcontroller 320 comprises amicrocomputer 326, a memory 324 and an interface 328. Themicrocontroller 320 can include a driver 322 that drives an atomizer(not shown). The driver 322 can include, e.g., a pulse-width modulator(PWM) or signal generator. The microcomputer 320 is configured toexecute a computer program, which can be stored externally or in thememory 324, to control operations of the eCig, including activation (anddeactivation) of the heating element. The memory 324 includes acomputer-readable medium that can store one or more segments or sectionsof computer code to carry out the processes described in the instantdisclosure. Alternatively (or additionally) code segments or codesections may be provide on an external computer-readable medium (notshown) that may be accessed through the interface 328.

It is noted that the microcontroller 320 may include an applicationspecific integrated circuit (IC), or the like, in lieu of themicrocomputer 326, driver 322, memory 324, and/or interface 328.

The microcontroller may be configured to log medium flow data, includingmass flow, volume flow, velocity data, time data, date data, flowduration data, and the like, that are associated with the medium flow.The medium may comprise an aerosol, a gas (e.g., air), a liquid, or thelike. The microcontroller may be configured not only to turn ON/OFF aheater based on such data, but to also adjust control parameters such asheater PWM or amount of liquid solution dispensed onto a heatingsurface. This control may be done proportionally to the flow data oraccording to an algorithm where flow data is a parameter. In addition,the microcontroller may use flow data to determine flow direction andrestrict or limit false activation of the heater in case the useraccidentally blows into the eCig.

FIG. 4 shows an example of a flow sensor 330 that is constructedaccording to an aspect of the disclosure. The flow sensor 330 comprisesa substrate 331 and a thermopile (e.g., two or more thermocouples),including an upstream thermopile (or thermocouple) 332 and a downstreamthermopile (or thermocouple) 333. The substrate 331 may include athermal isolation base. The flow sensor 130 may comprise a heaterelement 334. The flow sensor 330 may comprise a reference element 335.The heater element 334 may include a heater resistor. The referenceelement 335 may include a reference resistor.

As seen in FIG. 4, the thermopiles 332, 333 may be symmetricallypositioned upstream and downstream from the heater element 334. Theheater element 334 heats up the hot junctions of the thermopiles 332,333. In response, each of the thermopiles 332, 333 generates an outputvoltage that is proportional to the temperature gradient between its hotand cold junctions (the “Seebeck” effect). The hot junctions of thethermopiles 332, 333 and the heater element 334 may reside on thethermal isolation base. Mass airflow sensor signal conditioning may becomposed of various forms of filters or gain amplifiers. Filters may beused to eliminate noise before or after signal amplification, therebyreducing sensitivity to unwanted environmental noises or pressurechanges. Filtering can be accomplished using low pass, high pass, bandpass, or a combination thereof. Signal gain amplification may beaccomplished by employing electronic amplification on the upstream ordownstream thermopile signals, or a combination thereof. Amplificationof upstream or downstream thermopile signals may use a single state ormultiple cascaded stages for each signal, or combination of thesesignals to form a sum or difference. The amplifier circuit may includemeans to introducing a signal offset. The amplifier may includetransistors, operational amplifiers, or other integrated circuits.

FIGS. 5A and 5B illustrate an example of a single amplifier with afilter 364 and a difference amplifier and filters for upstream anddownstream, with offset 380. As shown in the single amplifier with afilter 364 in FIG. 5A, the airflow signal 360 passes through a filter361 and a gain amplifier 362 before a signal output 363 is transmitted.The difference amplifier and filters for upstream and downstream, withoffset 380 shown in FIG. 5B comprises an upstream airflow signal 370 anda downstream airflow signal 371. The upstream airflow signal 370 passesthrough a first filter 372 and the downstream airflow signal passesthrough a second filter 373. The outputs of the first and second filters371,372 then enter a difference amplifier 374. A signal is then outputfrom the difference amplifier 374 and enters a gain amplifier 375 alongwith an offset 375. The gain amplifier 376 then outputs a signal output377.

FIG. 6 illustrates an electrical diagram of an embodiment of thedisclosure comprising a first thermopile 452 and a second thermopile453. The eCig depicted in FIG. 6 comprises a microcontroller 440, a massairflow sensor 450, an amplifier 449, and a heater 456. The mass airflowsensor 450 comprises a mass airflow heater 451, a first thermopile 452,and a second thermopile 453. The electrical diagram further illustratesthe direction of airflow 454 over the mass airflow heater 451 and thefirst and second thermopiles 452, 453. The microcontroller 440 cancomprise a data acquisition circuit 441, and an analog-to-digitalconverter 442. The data acquisition circuit 441 can log and transmitdata such as temperature of the heater 456, the number of times theheater 456 has been activated in a certain time, the length of time theheater 456 had been activated, and other information. A more detaileddescription of data acquisition and transmission can be found incommonly assigned U.S. Provisional Application No. 61/907,239 filed 21Nov. 2013, the entire disclosure of which is hereby incorporated byreference as though fully set forth herein. The analog-to-digitalconverter 442 can output information about the eCig to themicrocontroller 440, the data acquisition circuit 441, and other devicesand sensors that may be present on the microcontroller 440 or otherwiseconnected to the eCig.

FIG. 7 illustrates an electrical diagram of another embodiment of thedisclosure comprising one thermopile 552. The eCig depicted in FIG. 7comprises a microcontroller 540, a mass airflow sensor 550, an amplifier549, and a heater 556. The mass airflow sensor 550 comprises a massairflow heater 551 and a thermopile 552. The electrical diagram furtherillustrates the direction of airflow over the heater 554 and thethermopile 552. The microcontroller 540 can comprise a data acquisitioncircuit 541, and an analog-to-digital converter 542. The dataacquisition circuit 541 can log and transmit data such as temperature ofthe heater 556, the number of times the heater 556 has been activated ina certain time, the length of time the heater 556 had been activated,and other information. The analog-to-digital converter 542 can outputinformation about the eCig to the microcontroller 540, the dataacquisition circuit 541, and other devices and sensors that may bepresent on the microcontroller 540 or otherwise connected to the eCig.In one embodiment, the eCig can also comprise feedback and gainresistors 557, 558. More information regarding the airflow sensor can befound in PCT Publication no. WO 2014/205263, filed 19 Jun. 2014, whichis incorporated by reference herein as though set forth in its entirety.

FIGS. 8A and 8B show an example of a flow channel according to theprinciples of the disclosure. As seen in FIGS. 8A and 8B, the flowchannel can be shaped in the vicinity of the sensor so as to direct amajority of flow over the sensing surface, thus increasing thesensitivity of the system. FIG. 8A depicts a top down view of oneembodiment of a flow channel 601. FIG. 8B depicts an end view of theflow channel 601 shown in FIG. 8A. The flow channel 601 comprises afirst side wall 603, a second side wall 605, a top wall 623, a bottomwall 625, an incoming airflow opening 611, an incoming airflow pathway607, a sensor assembly 615, an outgoing airflow pathway 609, and anoutgoing airflow opening 613. The first side wall 603, the second sidewall 605, the top wall 623, and the bottom wall 625 define the incomingairflow opening 611, the incoming airflow pathway 607, the outgoingairflow pathway 609, and the outgoing airflow opening 613. The incomingairflow opening 611 can allow air to enter the flow channel 601. Theincoming airflow pathway 607 can extend along a longitudinal axis of theflow channel 601. The incoming airflow pathway 607 can extend a distancealong the longitudinal axis and comprise enough volume so that any airentering the flow channel 601 through the incoming airflow opening 611creates a laminar flow before passing over the sensor assembly 615. Inone embodiment, to achieve a laminar flow over the sensor assembly, theincoming airflow pathway can comprise a longitudinal length of 1.5-2 mm.In other embodiments, the longitudinal length of the incoming airflowpathway can be adjusted in response to different dimensions and volumesof the flow channel. The sensitivity of the sensor assembly 615 can beincreased by decreasing the volume of the flow channel 601. However, bydecreasing the volume of the flow channel 601 a draw resistance for auser is increased. As the volume of the flow channel 601 increases thesignal quality decreases, but the draw resistance is decreased. Afterthe air has passed over the sensor assembly 615, the airflow can beturbulent as it passes through the rest of the system. The sensorassembly 615 can comprise a sensor 617. The sensor 617 can detect anairflow over the sensor assembly 615 and can further detect a mass ofairflow over the sensor assembly 615 and passing through the flowchannel 601. The airflow can move over the sensor along the airflow path619 In one embodiment, the sensor can comprise a mass airflow sensor. Inanother embodiment, the sensor can comprise a capacitive sensor. Afterpassing over the sensor assembly 615, an airflow through the flowchannel 601 can enter the outgoing airflow pathway 609 and exit the flowchannel 601 through the outgoing airflow opening 613. After leaving theflow channel 601, the airflow can enter an external airflow pathway 621.In one embodiment, the external airflow pathway 621 can be sealed suchthat any air entering the flow channel 601 and passing over the sensorassembly 615 can be routed through the flow channel 601 and the externalairflow pathway 621 to an atomizer (not shown).

In other embodiments, a diverter can be present after the airflow haspassed over the sensor assembly such that a portion of the air passesover the atomizer and a portion of the air diverts around the atomizer.In these embodiments, the electronic smoking device is configured to, atleast in part, pass the airflow over the atomizer. In one embodiment,the portion of air that passes over the atomizer can be 50% or greaterof the air that passes over the sensor assembly. In another embodiment,the portion of air that passes over the atomizer can be 50% or less ofthe air that passes over the sensor assembly. By diverting a portion ofthe airflow that passes over the sensor assembly, the amount of air thatpasses over the atomizer can be controlled and the amount of aerosol orvapor created by the atomizer can be regulated. In yet otherembodiments, an additional air inlet can be added downstream of thesensor assembly, such that additional air can be added to the airflowthat has passed over the sensor assembly. In one embodiment, adding anadditional air inlet downstream of the sensor assembly can decrease thesensitivity of the sensor signal, but can further dilute the vaporstream. In yet other embodiments, additional components can be added todivert or add airflow to the airflow stream after it has passed thesensor assembly. The additional components can be used to divert theairflow stream away from the atomizer, add additional air to the airflowstream, or impart additional airflow after the airflow stream has passedthe atomizer. In yet other embodiments, the airflow passing over thesensor assembly can comprise a first portion of the airflow passingthrough a downstream portion of the electronic smoking device. A secondportion of the airflow passing through an upstream portion of theelectronic smoking device can be diverted around the sensor assembly. Inone embodiment, the second portion of the airflow can join with thefirst portion of the airflow after the first portion of the airflow haspassed over the sensor assembly. In one embodiment, the atomizer cancomprise a heater. In other embodiments, the atomizer can comprise amechanical or thermal atomizer as would be known to one in the art. Inone embodiment, the flow channel can be defined by the foam and plasticportions of the battery housing as illustrated in FIGS. 2A and 2B. Inone embodiment, the foam portion of the flow channel can comprise aminimum compression ratio of 30%. When foam is used within the flowchannel, the foam can be compressed enough to keep the flow channelsealed, but not compressed to an extent that the foam intrudes into thechannel. In one embodiment, the foam can comprise a micro closed-sealfoam.

FIG. 9 illustrates a side view of one embodiment of a sensor assembly651. The sensor assembly 651 can comprise a support structure 653, asensor 655, a first layer 659, and a second layer 661. The supportstructure 653 can comprise a PCB or other component that can beelectrically coupled to the sensor 655. The sensor 655 can detect anairflow over the sensor assembly 651 and can further detect a mass ofairflow over the sensor assembly 651. In one embodiment, the sensor cancomprise a mass airflow sensor. In another embodiment, the sensor cancomprise a capacitive sensor. The first layer 659 and the second layer661 can be used to create an upper surface 663 that extends along anincoming portion 665 of the sensor assembly 651. The upper surface 663can comprise a height above the support structure 653 similar to theheight the sensor 655 extends above the support structure 653. The uppersurface 663 created by the first layer 659 and the second layer 661 canbe used to minimize turbulence created by an airflow passing through anairflow pathway 667 and over the sensor assembly 651. The first layer659 can comprise any one of a number of substances that can be usedduring a PCB manufacturing process. In one embodiment, the first layer659 can comprise copper. In other embodiments, the first layer 659 cancomprise solder mask, silkscreen, or any other material that can bedeposited on a PCB or other support structure. The second layer 661 cancomprise any one of a number of substances that can be used during a PCBmanufacturing process. In one embodiment, the second layer 661 cancomprise solder mask. In other embodiments, the second layer 661 cancomprise copper, silkscreen, or any other material that can be depositedon a PCB or other support structure. In one embodiment, a silkscreenlayer can be further deposited on top of the second layer 661. Thesematerials can be used during the manufacturing of the sensor assembly651. Using materials already present during the manufacture of a PCBcomponent, additional manufacturing costs can be limited. In oneembodiment, the sensor can be formed and then a backgrinding process canbe used to remove portions of the sensor that are not integral to thesensor. By backgrinding the sensor, the height of the sensor can bedecreased, requiring less additional material to be placed on thesupport structure. In one embodiment, after undergoing the backgrindingprocess the sensor can comprise a height of 0.1 mm. In anotherembodiment, after undergoing the backgrinding process the sensor cancomprise a height of 0.2 mm.

FIG. 10 depicts a schematic view of another embodiment of a sensorassembly 701. The sensor assembly 701 can comprise a support structure703, a sensor 705, a first structure component 707, and a secondstructure component 709. The sensor 705 can be coupled to the supportstructure 703. In one embodiment, the sensor 705 can be electricallycoupled to the support structure 703. The first structure component 707and the second structure component 709 can be coupled to the supportstructure 703. The first structure component 707 and the secondstructure component 709 can assist in securing the sensor 705 to thesupport structure 703. In another embodiment, the first structurecomponent 707 and the second structure component 709 can each comprisean upper surface adjacent to an upper surface of the sensor 705. Thefirst support structure 707 and the second support structure 709 can beused to assist in directing an airflow over the sensor 705 and tominimize air currents that could be disruptive or otherwise unwantedwhen air is passed over the sensor 705.

FIG. 11A illustrates another embodiment of a sensor assembly 751. Thesensor assembly 751 can comprise a support structure 753, a sensor baseportion 757, a sensor top portion 755, and a sensor transition region759. The support structure 753 can comprise a depression sized andconfigured to house the sensor base portion 757. When the sensor baseportion 757 is placed within the depression of the support structure753, the sensor top portion 755 can be above an upper portion of thesupport structure. The sensor transition region 759 can be lined up withan upper surface of the support structure 753. By securing the sensorbase portion 757 within a depression of the support structure 753, thesensor top portion 755 can minimize any effects of the sensor topportion 755 on airflow flowing past the sensor assembly 751. As statedabove, in other embodiments, additional material can be placed on thesupport structure to further minimize any effects, turbulence orotherwise, possibly caused on an airflow passing over the sensorassembly 751.

FIG. 11B illustrates the sensor of FIG. 11A. The sensor comprises thesensor base portion 757, the sensor top portion 755, and the sensortransition region 759. As described above, the sensor base portion 757can be placed within a depression in a support structure. In otherembodiments, the sensor base portion 757 can be coupled to a top surfaceof a support structure. The sensor top portion 755 can comprise theportion of the sensor that is needed to interact with an airflow passingover the sensor to measure an airflow rate. In one embodiment, thesensor transition region 759 can be denoted as separating the portion ofthe sensor that needs to be exposed to a passing airflow (the sensor topportion 755) and the portion of the sensor that does not need to beexposed to a passing airflow (the sensor bottom portion 757).

FIG. 12A depicts a schematic view of one embodiment of a flow channel801. The flow channel 801 can comprise an upper housing 803, a supportstructure 805, a support depression 807, a sensor 809, and an airflowpathway 811. The upper housing 803, the support structure 805, and thesensor 809 can define the airflow pathway 811. Air entering the flowchannel 801 can pass over the sensor 809 in the airflow direction 813.The support depression 807 can be sized and configured to house a lowerportion of the sensor 809. When the lower portion of the sensor 809 isplaced within the support depression 807, an upper portion of the sensor809 can be above an upper surface of the support structure 805. Bysecuring the sensor 809 within the support depression 807, the sensor809 can minimize any effects on airflow flowing past the sensor 809. Asstated above, in other embodiments, additional material can be placed onthe support structure to further minimize any effects, turbulence orotherwise, possibly caused on an airflow passing over the sensor 809.The upper housing can comprise a variety of materials. In oneembodiment, the upper housing can comprise plastic. In anotherembodiment, the upper housing can comprise tape placed over the flowchannel. In yet other embodiments, the upper housing can comprise anyother material that can withstand deformation from air flowing throughthe airflow pathway.

FIG. 12B depicts a schematic view of another embodiment of a flowchannel 831. The flow channel 831 can comprise an upper housing 833, asupport structure 835, a sensor 837, a first structure component 841, asecond structure component 839, and an airflow pathway 843. The upperhousing 833, the support structure 835, the first structure component841, the second structure component 839, and the sensor 837 can definethe airflow pathway 843. Air entering the flow channel 831 can pass overthe sensor 837 in the airflow direction 845. The sensor 837 can becoupled to the support structure 835. In one embodiment, the sensor 837can be electrically coupled to the support structure 835. The firststructure component 841 and the second structure component 839 can becoupled to the support structure 835. The first structure component 841and the second structure component 839 can assist in securing the sensor837 to the support structure 835. In another embodiment, the firststructure component 841 and the second structure component 839 can eachcomprise an upper surface adjacent to an upper surface of the sensor837. The first support structure 841 and the second support structure839 can be used to assist in directing an airflow over the sensor 837and to minimize air currents that could be disruptive or otherwiseunwanted when air is passed over the sensor 837. The upper housing cancomprise a variety of materials. In one embodiment, the upper housingcan comprise plastic. In another embodiment, the upper housing cancomprise tape placed over the flow channel. In yet other embodiments,the upper housing can comprise any other material that can withstanddeformation from air flowing through the airflow pathway.

FIG. 12C depicts a schematic view of another embodiment of a flowchannel 861. The flow channel 861 can comprise an upper housing 863, afirst side support structure 865, a second side support structure 879, asensor support structure 867, a sensor 869, an airflow pathway 871, anairflow sensor entrance 875, and an airflow sensor exit 877. The upperhousing 863, the first side support structure 865, the second sidesupport structure 879, the sensor support structure 867, and the sensor869 can define the airflow pathway 871. The first side support structure865 and the sensor support structure 867 can define an airflow sensorentrance 875. The sensor support structure 867 and the second sidesupport structure 879 can define an airflow sensor exit 877. Airentering the flow channel 861 can enter through the airflow sensorentrance 875, can pass over the sensor 869, and can exit through theairflow sensor exit 877 in the airflow direction 873. As describedabove, the sensor 869 can be placed within a depression in the sensorsupport structure 867. The upper housing can comprise a variety ofmaterials. In one embodiment, the upper housing can comprise plastic. Inanother embodiment, the upper housing can comprise tape placed over theflow channel. In yet other embodiments, the upper housing can compriseany other material that can withstand deformation from air flowingthrough the airflow pathway.

FIG. 13 depicts a graph illustrating one embodiment of the powerdelivered for a given flow rate 901. The depicted graph illustrates aresponse curve 903 showing a logarithmic graph with a power level for asensed airflow rate. As seen in in the illustrated embodiment, a firstposition 905 on the graph comprises a power level of 4 W that can beoutput to an atomizer at a first flow rate. A second position 907 on thegraph comprises a power level of 10 W that can be output to an atomizerat a second flow rate. The response curve comprises a logarithmic curvewhere the power output is exponential in response to the flow rate. Anexponential increase in power output can be used as an atomizer may notbe properly heated with an increasing rate of airflow using a linearresponse. In other embodiments, the power output can be increased in anexponential fashion in response to an increased airflow so that theatomizer can deliver a larger amount of aerosol in response to a largeror faster rate of airflow over the sensor and through the system as awhole. The larger amount of aerosol produced by the atomizer can attemptto mimic the increased amount of smoke that can be produced by a userwho takes a deeper or longer drag on a traditional cigarette. In anotherembodiment, where an increase in aerosol is not desired, the poweroutput can comprise a linear increase as airflow is increased.

FIG. 14 depicts a graph illustrating several embodiments of response toflow rate 921. The response illustrated in FIG. 14 is the response fromthe airflow sensor for a given flow rate. The graph illustrates a firstresponse curve 923, a second response curve 925, and a third responsecurve 927. Each of the first response curve 923, the second responsecurve 925, and the third response curve 927 illustrate a response fromdifferent individual airflow sensors. The second response curve 925further depicts a plurality of response points 929. The plurality ofresponse points can each individually comprise a known response for agiven flow rate. In another embodiment, only a portion of the pluralityof response points 929 can be determined during testing and other of theplurality of response points 929 can be determined by calculating acurve to fit the determined response points. As shown in FIG. 14, afirst response flow rate 931 can comprise a 5 ml/s flow rate and asecond response flow rate 935 can comprise a 40 ml/s flow rate.

FIG. 15 depicts a graph illustrating one embodiment of a flow v timeoutput 941. The flow v time output 941 comprises a user puff 943. Theuser puff 943 comprises a varying flow rate over time. As shown in thedepicted user puff 943, initially the flow rate is negligible. At alater time, a user initiates the puff, and the flow rate increases untilit reaches a maximum flow rate. The flow rate then slowly lowers overthe course of time, until dropping back to the initial negligible flowrate.

FIG. 16 depicts a graph illustrating several embodiments of response toflow rate 961. As seen in FIG. 14, the response illustrated is theresponse from the airflow sensor for a given flow rate. The graphillustrates a first response curve 963, a second response curve 965, athird response curve 967, and a fourth response curve 969. Each of thefirst response curve 963, the second response curve 965, the thirdresponse curve 967, and the fourth response curve 969 illustrate aresponse from different individual airflow sensors. As seen in theillustrated embodiments, all of the sensors have different curves anddifferent baseline conditions. The signals from each sensor can then bedriven higher or lower to bring each sensor to a common baseline signal.Even after a common baseline signal has been assigned, each sensor stilldisplays a different curve. The curve for each sensor can be calculatedby determining the response signal for a subset of airflow rates. In oneembodiment, three response signals can be determined to calculate theresponse curve. In the illustrated embodiment, the response signals canbe determined at a first response location 971, a second responselocation 973, and a third response location 975. In one embodiment thethree response signals can be recorded at 15 ml/s, 25 ml/s, and 40 ml/s.The response signal received at each of the three flow rates can be usedto calibrate the response curve. Each of the sensors comprises aresponse curve that is logarithmic or exponential. The response curvecan be used to generate a table of points 979 that can be looked up bythe system. The number of points within the look up table can vary. Inone embodiment, the look up table can comprise 32 values. Otherembodiments can have fewer or more points within the look up table. Inanother embodiment, an equation can be used to determine a flow rate fora specific signal. In another embodiment, the look up table can belimited in maximum range to what can be performed by a user using thedevice. In one embodiment, that upper range can comprise 40 ml/s to 50ml/s. Further, the lowest airflow that an average user will be able tosustain for a light puff is about 15 ml/s. As a result, the normal rangethat can be used within the lookup table is 15 ml/s to 40 ml/s. Inanother embodiment, the normal range that can be used within the lookuptable is 15 ml/s to 50 ml/s. In yet another embodiment, the normal rangethat can be used is 5 ml/s to 50 ml/s. In yet other embodiments, otherranges can be used. In one embodiment, the responsiveness can be scaledin terms of power output within that range. In another embodiment, anairflow rate above 35 ml/s will not increase a power output to theatomizer. In yet another embodiment, an airflow rate below 15 ml/s willnot decrease the power output to the atomizer. Further, in oneembodiment, the values included in the look up table are not evenlyspread out. In this embodiment, the values above 35 ml/s can be furtherapart than those below 35 ml/s. In another embodiment, a thresholdairflow rate of 5 ml/s can be used to start a puff event. While 5 ml/sairflow rate can be used to start a puff event, the coil does notenergize until an airflow rate of 10 ml/s occurs. In one embodiment, thebaseline value ceases updating after the puff event starts at 5 ml/s.Further, in another embodiment, the atomizer starts energizing at 10ml/s, and then once the airflow rate decreases below 10 ml/s, theatomizer stops energizing. Further, the puff event stops after theairflow rate drops below 5 ml/s. Further, in other embodiments, theenergization and puff event values can comprise different amounts thanthose listed herein.

FIG. 17 illustrates a flow-chart of the process by which themicrocontroller or other component can interpret signals from the massairflow sensor or other device. In step 1000 a microcontroller canmonitor a sensor signal sent from the mass airflow sensor. When themicrocontroller monitors a change in the sensor signal that is beingmonitored in step 1000, the microcontroller can determine if the changein the sensor signal is below a programmed threshold 1001. If the changein the sensor signal over a length of time is below the programmedthreshold the microcontroller or other component can alter a referencesignal and a relation signal to a predetermined baseline 1002. In oneembodiment the reference signal can be set to a baseline reading of 2.0volts. The microcontroller than continues to monitor the mass airflowsensor for a change in the sensor signal 1000. If the change in thesensor signal over time is above a programmed threshold 1001, then themicrocontroller or other component reads the difference between thereference signal and the relation signal 1003. In step 1004, themicrocontroller or other component can operate a device, sensor, orother component according to the difference between the reference signaland the relation signal. The process then goes back to step 1000 and themicrocontroller or other component continues to monitor the mass airflowsensor for a change in the sensor signal over time.

The sensor can drift as the temperature of the sensor increases. Thedrift can comprise about 0.1% per degree Celsius. While the drift canappear minimal, at higher end flow rates, because of the low overallsignal, the small difference can make a big difference in the sensedairflow rate. To account for the temperature drift error two approachescan be used. The first approach is to add a thermistor to the sensor.This thermistor can be powered through the offset and the resistance ofthe thermistor can vary with temperature. The resistance can be sampledand the temperature of the sensor can be determined. The second approachcan use the sensor itself and look at the value output by the sensorwhen a puff event starts and use this signal as a baseline. A baselineof when a puff event is not occurring and a signal output by the sensorwhen a puff event occurs. The baseline signal when a puff event is notoccurring will tend to shift slightly. This shift can be correlated totemperature. In one embodiment, a look up table can be used to determinea temperature shift. In another embodiment, an algorithm can be used todetermine a temperature shift. The temperature shift described hereincan be used for any airflow sensor, including mass airflow sensors,capacitive sensors, or others as would be known to one of ordinary skillin the art.

Various embodiments of the present disclosure are directed to anelectronic smoking device. The electronic smoking device can comprise aflow channel and an atomizer. The flow channel can comprise an incomingairflow opening, an incoming airflow pathway, a sensor assembly, and anoutgoing airflow opening. The atomizer can be fluidly coupled to theflow channel. The flow channel can be configured to direct an airflowfrom the incoming airflow opening, through the incoming airflow pathway,over the sensor assembly, and through the outgoing airflow opening. Theelectronic smoking device can further be configured to pass the airflow,at least in part, over the atomizer. In a more specific embodiment, theelectronic smoking device can further comprise an outgoing airflowpathway between the sensor assembly and the outgoing airflow opening. Ina more specific embodiment, the electronic smoking device can furthercomprise an external airflow pathway coupled to the flow channel,wherein the external airflow pathway is configured to direct air fromthe outgoing airflow opening to the atomizer.

In a more specific embodiment, the flow channel further comprises afirst side wall, a second side wall, a bottom wall, and a top wall, andwherein the first side wall, the second side wall, the bottom wall, andthe top wall define the incoming airflow opening. In a more specificembodiment, the flow channel is sized and configured to create a laminarflow of air in the incoming airflow pathway before the airflow reachesthe sensor assembly. In some embodiments, the sensor assembly comprisesa support structure and a sensor, and wherein the sensor is coupled tothe support structure. In other embodiments, the sensor assembly furthercomprises a first layer and a second layer coupled to the supportstructure. In yet other embodiments, the first layer and the secondlayer create an upper surface. In other embodiments, the upper surfacecomprises a height above the support structure similar to a height ofthe sensor. In yet other embodiments, the upper surface is configured tominimize turbulence of the airflow over the sensor. In some embodiments,the first layer comprises copper. In other embodiments, the second layercomprises solder mask. In yet other embodiments, the sensor assemblyfurther comprises a silkscreen material deposited on top of the secondlayer.

In another embodiment, the support structure comprises a PCB. In yetanother embodiment, the support structure comprises a supportdepression. In other embodiments, a lower portion of the sensor is sizedand configured to fit within the support depression. In someembodiments, the sensor assembly further comprises a sensor, and whereinthe sensor comprises a height of no more than 0.2 mm.

Other various embodiments consistent with the present disclosure aredirected to an electronic smoking device. The electronic smoking devicecan comprise a flow channel. The flow channel can comprise an incomingairflow opening, an incoming airflow pathway, a sensor assembly, and anoutgoing airflow opening. The flow channel can be configured to directan airflow from the incoming airflow opening, through the incomingairflow pathway, over the sensor assembly, and through the outgoingairflow opening. In other various embodiments, the flow channel is sizedand configured to create a laminar flow of air in the incoming airflowpathway before the airflow reaches the sensor assembly. In yet otherembodiments, the sensor assembly comprises a support structure, a firstlayer, a second layer, and a sensor, and wherein the sensor, the firstlayer, and the second layer are coupled to the support structure.

It should be noted that the features illustrated in the drawings are notnecessarily drawn to scale, and features of one embodiment may beemployed with other embodiments as the skilled artisan would recognize,even if not explicitly stated herein. Descriptions of well-knowncomponents and processing techniques may be omitted so as to notunnecessarily obscure the embodiments of the disclosure. The examplesused herein are intended merely to facilitate an understanding of waysin which the disclosure may be practiced and to further enable those ofskill in the art to practice the embodiments of the disclosure.Accordingly, the examples and embodiments herein should not be construedas limiting the scope of the disclosure. Moreover, it is noted that likereference numerals represent similar parts throughout the several viewsof the drawings.

The terms “including,” “comprising” and variations thereof, as used inthis disclosure, mean “including, but not limited to,” unless expresslyspecified otherwise.

The terms “a,” “an,” and “the,” as used in this disclosure, means “oneor more,” unless expressly specified otherwise.

Although process steps, method steps, algorithms, or the like, may bedescribed in a sequential order, such processes, methods and algorithmsmay be configured to work in alternate orders. In other words, anysequence or order of steps that may be described does not necessarilyindicate a requirement that the steps be performed in that order. Thesteps of the processes, methods or algorithms described herein may beperformed in any order practical. Further, some steps may be performedsimultaneously.

When a single device or article is described herein, it will be readilyapparent that more than one device or article may be used in place of asingle device or article. Similarly, where more than one device orarticle is described herein, it will be readily apparent that a singledevice or article may be used in place of the more than one device orarticle. The functionality or the features of a device may bealternatively embodied by one or more other devices which are notexplicitly described as having such functionality or features.

Although several embodiments have been described above with a certaindegree of particularity, those skilled in the art could make numerousalterations to the disclosed embodiments without departing from thespirit of the present disclosure. It is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative only and not limiting. Changes indetail or structure may be made without departing from the presentteachings. The foregoing description and following claims are intendedto cover all such modifications and variations.

Various embodiments are described herein of various apparatuses,systems, and methods. Numerous specific details are set forth to providea thorough understanding of the overall structure, function,manufacture, and use of the embodiments as described in thespecification and illustrated in the accompanying drawings. It will beunderstood by those skilled in the art, however, that the embodimentsmay be practiced without such specific details. In other instances,well-known operations, components, and elements have not been describedin detail so as not to obscure the embodiments described in thespecification. Those of ordinary skill in the art will understand thatthe embodiments described and illustrated herein are non-limitingexamples, and thus it can be appreciated that the specific structuraland functional details disclosed herein may be representative and do notnecessarily limit the scope of the embodiments, the scope of which isdefined solely by the appended claims.

Reference throughout the specification to “various embodiments,” “someembodiments,” “one embodiment,” “an embodiment,” or the like, means thata particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.Thus, appearances of the phrases “in various embodiments,” “in someembodiments,” “in one embodiment,” “in an embodiment,” or the like, inplaces throughout the specification are not necessarily all referring tothe same embodiment. Furthermore, the particular features, structures,or characteristics may be combined in any suitable manner in one or moreembodiments. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment may be combined, in whole or in part, with the featuresstructures, or characteristics of one or more other embodiments withoutlimitation.

It will be appreciated that the terms “proximal” and “distal” may beused throughout the specification with reference to a clinicianmanipulating one end of an instrument used to treat a patient. The term“proximal” refers to the portion of the instrument closest to theclinician and the term “distal” refers to the portion located furthestfrom the clinician. It will be further appreciated that for concisenessand clarity, spatial terms such as “vertical,” “horizontal,” “up,” and“down” may be used herein with respect to the illustrated embodiments.However, surgical instruments may be used in many orientations andpositions, and these terms are not intended to be limiting and absolute.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialsdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

While this invention has been described in connection with what ispresently considered to be practical exemplary embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but, on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the scope ofthe appended claims.

LIST OF REFERENCE SIGNS

-   10 electronic smoking device-   12 end cap-   14 power supply portion-   16 atomizer/liquid reservoir portion-   18 light-emitting diode (LED)-   20 air inlets-   22 battery-   24 control electronics-   26 airflow sensor-   28 atomizer-   30 heating coil-   32 wick-   34 central passage-   36 liquid reservoir-   38 air inhalation port-   212 power supply portion-   213 power supply portion sub-assembly-   216 circumferential light guide-   218 battery-   220 LED-   221 flexible printed circuit board-   222 controller circuitry-   224 airflow sensor-   225 contacts-   226 locking pin-   227 airflow gasket-   228 MAF gasket-   229 spacer-   240 upper sub-assembly housing-   241 lower sub-assembly housing-   242 wire lead-   245 tube-   246 tip diffuser-   248 pattern-   258 female connector port-   320 microcontroller-   322 driver-   324 memory-   326 microcomputer-   328 interface-   330 flow sensor-   331 substrate-   332 upstream thermopile-   333 downstream thermopile-   334 heater element-   335 reference element-   360 airflow signal-   361 filter-   362 gain amplifier-   363 signal output-   364 filter-   370 upstream airflow signal-   371 downstream airflow signal-   372 first filter-   373 second filter-   374 difference amplifier-   375 gain amplifier-   376 offset-   377 signal output-   380 offset-   440 microcontroller-   441 data acquisition circuit-   442 analog-to-digital converter-   449 amplifier-   450 mass airflow sensor-   451 mass airflow heater-   452 first thermopile-   453 second thermopile-   454 direction of airflow-   456 heater-   540 microcontroller-   541 data acquisition circuit-   542 analog-to-digital converter-   549 amplifier-   550 mass airflow sensor-   551 mass airflow heater-   552 thermopile-   554 heater-   556 heater-   557 feedback resistor-   558 gain resistor-   601 flow channel-   603 first side wall-   605 second side wall-   607 incoming airflow pathway-   609 outgoing airflow pathway-   611 incoming airflow opening-   613 outgoing airflow opening-   615 sensor assembly-   617 sensor-   619 airflow path-   621 external airflow pathway-   623 top wall-   625 bottom wall-   651 sensor assembly-   653 support structure-   655 sensor-   659 first layer-   661 second layer-   663 upper surface-   665 incoming portion-   667 airflow pathway-   701 sensor assembly-   703 support structure-   705 sensor-   707 first structure component-   709 second structure component-   751 sensor assembly-   753 support structure-   755 sensor top portion-   757 sensor base portion-   759 sensor transition region-   801 flow channel-   803 upper housing-   805 support structure-   807 support depression-   809 sensor-   811 airflow pathway-   813 airflow direction-   831 flow channel-   833 upper housing-   835 support structure-   837 sensor-   839 second structure component-   841 first structure component-   843 airflow pathway-   845 airflow direction-   861 flow channel-   863 upper housing-   865 first side support structure-   867 sensor support structure-   869 sensor-   871 airflow pathway-   873 airflow direction-   875 airflow sensor entrance-   877 airflow sensor exit-   879 second side support structure-   901 power delivered for a given flow rate-   903 response curve-   905 first position-   907 second position-   921 response to flow rate-   923 first response curve-   925 second response curve-   927 third response curve-   929 plurality of response points-   931 first response flow rate-   935 second response flow rate-   941 flow v time output-   943 user puff-   1000 microcontroller monitoring sensor-   1001 change over time below threshold-   1002 normalize reference signal and relation signal-   1003 read difference between reference signal and relation signal-   1004 operate device

I claim:
 1. An electronic cigarette comprising: a power supply housinghaving a first and second end, a subassembly housing holding a battery;a first circuit board at the first end of the power supply housing, thefirst circuit board having a plurality of LEDs, the first circuit boardconnected to a second circuit board by an electrical connectionextending along a length of the battery; the second circuit board at thesecond end of the power supply housing; an air flow sensor on the secondcircuit board; and a light guide at the first end of the power supplyhousing.
 2. The electronic cigarette of claim 1 wherein the light guideilluminates the power supply housing when the LEDs are on.
 3. Theelectronic cigarette of claim 1 having five LEDs.
 4. The electroniccigarette of claim 1 wherein LEDs provide a plurality of visualindications by varying the brightness, color, and on/off time of theLEDs.
 5. The electronic cigarette of claim 4 wherein the indicationsreflect a functional aspect of the electronic cigarette.
 6. Theelectronic cigarette of claim 5 wherein the functional aspect is one ormore of remaining battery life, battery charging, and/or sleep mode. 7.The electronic cigarette of claim 1 further including controllercircuitry on the second circuit board.
 8. The electronic cigarette ofclaim 1 further including a tip diffuser at the first end of the powersupply housing.
 9. The electronic cigarette of claim 1 further includinga locking element locking the subassembly housing with the power supplyhousing.
 10. The electronic cigarette of claim 1 further including oneor more keying features on the subassembly housing for preventingrotation of the subassembly housing about a longitudinal axis.
 11. Theelectronic cigarette of claim 1 wherein first circuit board comprises isa printed flex circuit.
 12. The electronic cigarette of claim 11 whereinprinted flex circuit extends over the battery and around an end of thebattery.
 13. An electronic cigarette power supply assembly comprising: apower supply housing having a first and second end, a subassemblyhousing holding a battery a first printed circuit board positioned atthe first end of the power supply housing, the first printed circuitboard having a plurality of LEDs, the first printed circuit boardconnected to a second printed circuit board by an electrical connectionextending alongside of the battery; the second printed circuit boardlocated at the second end of the power supply housing; an air flowsensor attached to the second printed circuit board; and a light guideat the second end of the power supply housing.
 14. The electroniccigarette power supply assembly of claim 13 further including aconnector port in the power supply housing.
 15. The electronic cigarettepower supply assembly of claim 14 further including an airflow gasket inthe connector port.
 16. The electronic cigarette power supply assemblyof claim 13 further including control circuitry on the second printedcircuit board.
 17. The electronic cigarette power supply assembly ofclaim 16 further including contacts on the second printed circuit boardelectrically coupled to the controller circuitry, the contacts extendingtoward apertures within the upper sub-assembly housing.